Liquid administration tool

ABSTRACT

A liquid administration device includes a structure that includes an accommodation body configured to accommodate liquid therein and a needle configured to communicate with an inside of the accommodation body; an operation unit configured to discharge the liquid inside the accommodation body from the needle by moving toward the structure in a distal direction; a cover member that is movable between a protection position at which the needle is covered and an exposure position at which the needle is exposed; a first biasing member that biases the operation unit toward the structure in the distal direction; and a second biasing member that biases the cover member in the distal direction. The operation unit has a first contact portion and the structure has a second contact portion, the contact portions being configured to come into contact with each other when the operation unit moves toward the structure in the distal direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2014-047698, filed on Mar. 11, 2014 which is hereby incorporated byreference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a liquid administration device foradministering a liquid into a living body.

2. Background Art

In the related art, a prefilled syringe, which is previously filled witha liquid such as a medicine, is known. In general, the prefilled syringeincludes a syringe outer cylinder in which a liquid is accommodated andthat is formed with a discharge port at a distal end through which theliquid is discharged, a needle tube that is provided in the dischargeport of a syringe outer cylinder, a gasket that is slidable in thesyringe outer cylinder, and a plunger for pressing the gasket in adistal direction.

The prefilled syringe is also used when a patient performs selfadministration at home. However, in some cases, its operation isdifficult when the elderly and women who are weak, rheumatism patientswho have a pain or deformation in the fingers, and the like perform selfadministration.

For example, US2005/0171477A discloses an auto-injector that is aprefilled syringe automatically performing administration using springforce. When using the auto-injector, a trigger that maintains a springin a state of being contracted is released by pushing the housing to aliving body and pressing an end portion of the housing. The living bodyis punctured with a needle tube protruding from the housing due to abiasing force of the released spring. Then, a plunger moves in a distaldirection due to the biasing force of the spring, and a medicine isautomatically administered into the living body through the needle tube.

In the auto-injector, once administration is started, the administrationis continued up to the end of the administration. For this reason, it isimpossible to suspend the administration even if it is necessary totemporarily suspend the administration for reasons such as avoidance ofpain.

SUMMARY OF INVENTION

In light of the foregoing, one objective of certain embodiments of thepresent invention is to provide a liquid administration device withwhich it is possible to temporarily stop administration.

According to one embodiment, a liquid administration device is used foradministering a liquid into a living body, and includes a structure thatincludes an accommodation body capable of accommodating the liquidtherein and a needle tube communicatable with the inside of theaccommodation body, an operation unit for discharging the liquid insidethe accommodation body from the needle tube by moving to the structurein a distal direction, a cover member that is movable between aprotection position at which the needle tube is covered and an exposureposition from which the needle tube is exposed, a first biasing memberthat biases the operation unit to the structure in the distal direction,and a second biasing member that biases the cover member in the distaldirection. The operation unit and the structure have a first contactportion and a second contact portion that come into contact with eachother while changing a contact position when the operation unit moves tothe structure in the distal direction and that apply a pressing force toeach other.

The liquid administration device that is configured as described aboveis provided with the first contact portion and the second contactportion coming into contact with each other while applying pressingforce to each other. Therefore, it is possible to impart contactresistance against the biasing force of the first biasing member and tosuspend administration by stopping pressing of the operation unit whenit is necessary to temporarily suspend the administration.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side surface view showing a liquid administration deviceaccording to a first embodiment.

FIG. 2 is a longitudinal cross-sectional view showing the liquidadministration device according to the first embodiment.

FIG. 3 is a perspective cross-sectional view that is partially cut andshows the liquid administration device according to the firstembodiment.

FIG. 4 is a perspective view showing an operation unit cylinder.

FIG. 5 is a perspective view showing an operation unit proximal member.

FIG. 6 is a perspective view showing an engagement plate.

FIG. 7 is a perspective view showing a plunger.

FIG. 8 is a perspective view showing a cover member.

FIG. 9 is a perspective view showing a rotary cylinder proximal portion.

FIGS. 10(A) and 10(B) are views showing a rotary cylinder distalportion. FIG. 10(A) is a perspective view having a cam groove as acenter and FIG. 10(B) is a perspective view having a safety groove as acenter.

FIG. 11 is a plan view showing the rotary cylinder distal portion.

FIGS. 12(A) and 12(B) are side surface views for illustrating the liquidadministration device according to the first embodiment in a firstoperation state. FIG. 12(A) shows an operation guide portion and FIG.12(B) shows an exposure restriction unit.

FIGS. 13(A) and 13(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the cover member moves to the structure. FIG. 13(A) shows theoperation guide portion and FIG. 13(B) shows the exposure restrictionunit.

FIG. 14 is a cross-sectional view showing a state in which the covermember of the liquid administration device according to the firstembodiment is moved and an object is punctured with a needle tube.

FIG. 15 is a perspective cross-sectional view that is partially cut andshows the state in which the cover member of the liquid administrationdevice according to the first embodiment is moved and an object ispunctured with the needle tube.

FIGS. 16(A) and 16(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the operation unit is further pressed after the cover membermoves to the structure. FIG. 16(A) shows the operation guide portion andFIG. 16(B) shows the exposure restriction unit.

FIG. 17 is a perspective cross-sectional view that is partially cut andshows a state in which a guiding convex portion of the liquidadministration device according to the first embodiment stops at aholding portion for suspension.

FIG. 18 is a cross-sectional view showing a state in which a liquid isadministered using the liquid administration device according to thefirst embodiment.

FIGS. 19(A) and 19(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the pressing of the operation unit is released. FIG. 19(A)shows the operation guide portion and FIG. 19(B) shows the exposurerestriction unit.

FIGS. 20(A) and 20(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the operation unit is pressed again after a temporary stop.FIG. 20(A) shows the operation guide portion and FIG. 20(B) shows theexposure restriction unit.

FIG. 21 is a cross-sectional view showing a state in whichadministration of the liquid using the liquid administration deviceaccording to the first embodiment is completed.

FIGS. 22(A) and 22(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the operation unit reaches a movement amount for thecompletion of the administration of the liquid. FIG. 22(A) shows theoperation guide portion and FIG. 22(B) shows the exposure restrictionunit.

FIGS. 23(A) and 23(B) are side surface views illustrating the liquidadministration device according to the first embodiment in an operationstate when the administration of the liquid is complete and the cover isseparated from the object. FIG. 23(A) shows the operation guide portionand FIG. 23(B) shows the exposure restriction unit.

FIG. 24 is a cross-sectional view showing a state in which the liquidadministration device according to the first embodiment is covered witha cap.

FIG. 25 is a perspective view showing a plunger of a liquidadministration device according to a second embodiment.

FIGS. 26(A) and 26(B) are side surface views illustrating the liquidadministration device according to the second embodiment in an operationstate when the cover member moves to the structure. FIG. 26(A) shows anoperation guide portion and FIG. 26(B) shows an exposure restrictionunit.

FIGS. 27(A) and 27(B) are side surface views illustrating the liquidadministration device according to the second embodiment in an operationstate when the administration of the liquid is complete and the cover isseparated from an object. FIG. 27(A) shows the operation guide portionand FIG. 27(B) shows the exposure restriction unit.

FIG. 28 is a perspective view showing a plunger of a modificationexample of the liquid administration device according to the firstembodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described withreference to accompanying drawings. Note that, in some cases,dimensional ratios in the drawings are exaggerated and are differentfrom the actual ratios for the convenience of description. In addition,in the description below, the operation side (side on which a userpresses) of a liquid administration device will be referred to as a“proximal side”, and the side from which a needle tube protrudes andthrough which a liquid is administered will be referred to as a “distalside”.

First Embodiment

A liquid administration device 10 according to a first embodiment shownin FIGS. 1 to 3 is a medical device for administering a liquid such as amedicine into a living body.

The liquid administration device 10 includes an operation unit 20 (upperhousing) that is gripped and operated by a user, a cover member 30 thatis provided so as to be movable to the operation unit 20, a structure 40that is provided so as to be rotatable inside the operation unit 20 andthe cover member 30, a second coil spring 11 (second biasing member)that biases the cover member 30 to the structure 40 in the distaldirection, and a first coil spring 12 (first biasing member) that isdisposed inside the operation unit 20. In general, the liquidadministration device 10 is provided in a state in which the covermember 30 and a needle tube 66 are covered with a cap 120 that is thenremoved for use.

The operation unit 20 is a part that a user grips and at whichadministration of a liquid is operated. The operation unit includes acylindrical operation unit cylinder 70 that a user grips and presses, anoperation unit proximal member 80 that is provided so as to close anopening of a proximal side of the operation unit cylinder 70, a plunger90, an engagement plate 50 that is interposed between the operation unitcylinder 70 and the operation unit proximal member 80 and is engagedwith the first coil spring 12, and a gasket 21 that is pressed and movedby the plunger 90.

As shown in FIGS. 1 to 4, the operation unit cylinder 70 is disposed soas to surround an outer peripheral surface of the structure 40 and isformed with a first window portion 71, through which it is possible toobserve the inside from the outside, and two operation unit engagementholes 72 for engaging the operation unit proximal member 80. Inaddition, two operation unit first grooves 73 and two operation unitsecond grooves 74 that extend in an axial direction and two positioningconcave portions 75 are formed on an inner peripheral surface of theoperation unit cylinder 70.

The first window portion 71 is formed into a through-hole penetratingfrom the outer peripheral surface to the inner peripheral surface. Inaddition, the first window portion may be formed of a transparentmaterial. The structure 40 and the cover member 30 that are disposedinside the operation unit cylinder 70 can be observed through the firstwindow portion 71. It is possible to grasp the progress ofadministration by members observed through the first window portion 71.

Two operation unit engagement holes 72 are provided at positionsopposite to each other across a central axis of the operation unit 20and are formed into through-holes penetrating from the outer peripheralsurface to the inner peripheral surface. Note that the operation unitengagement holes 72 do not have to be the through-holes as long as theoperation unit proximal member 80 can be engaged therewith.

The two operation unit first grooves 73 are provided at positionsopposite to each other across the central axis of the operation unit 20and each accommodates a guiding rib 33 (refer to FIG. 8) formed on anouter peripheral surface of the cover member 30 to be described later soas to be movable in an axial direction. The two operation unit secondgrooves 74 are provided at positions opposite to each other across thecentral axis of the operation unit and each accommodates a separationprevention convex portion 34 (refer to FIG. 8) that is formed on theouter peripheral surface of the cover member 30 to be described later soas to be movable in the axial direction. A pullout prevention rib 74Afor preventing the cover member 30 from being pulled out is formed inthe middle of the operation unit second groove 74.

As shown in FIGS. 1 to 3 and 5, the operation unit proximal member 80includes two operation unit engagement claws 81 that are engaged withthe operation unit cylinder 70, two noise generation claws 82 (noisegeneration portions) for generating noise by being engaged with a rotarycylinder proximal portion 100, and a plunger interlock hole 83 forinterlocking the plunger 90.

The two operation unit engagement claws 81 are provided at positionsopposite to each other across the central axis of the operation unit 20therebetween and can be engaged with the operation unit engagement holes72 of the operation unit cylinder 70. With the engagement of theoperation unit engagement claw 81 with the operation unit engagementhole 72, the operation unit cylinder 70 along with the operation unitproximal member 80 and the plunger 90 along with the engagement plate 50that are interposed therebetween are constituted so as to be integrallymoved.

The plunger interlock hole 83 is formed in a central portion of theoperation unit proximal member 80, and a proximal side part of theplunger 90 can be inserted therein.

As shown in FIGS. 1 to 3 and 6, the engagement plate 50 is a disc-shapedmember disposed so as to be interposed between the operation unitcylinder 70 and the operation unit proximal member 80. The engagementplate 50 is formed with a plunger insertion hole 51 through which theplunger 90 is inserted, two noise generation insertion holes 52 throughwhich the noise generation claws 82 are penetrated, two engagement clawinsertion holes 53 through which the operation unit engagement claws 81are penetrated, and two positioning convex portions 57. A springengagement portion 54 that protrudes toward the proximal side and withwhich the first coil spring 12 is engaged is formed at an inner edge ofthe engagement claw insertion hole 53 on the proximal side.

The two noise generation insertion holes 52 are provided at positionsopposite to each other across a central axis of the engagement plate 50.The two engagement claw insertion holes 53 are provided at positionsopposite to each other across the central axis of the engagement plate50 therebetween.

The spring engagement portion 54 is formed within a predetermined anglerange in a circumferential direction and is formed with a springmovement slope 55 of which the protruding height of the springengagement portion in the proximal direction inclines in thecircumferential direction. The spring movement slope 55 is a part withwhich a spring proximal portion 12A (refer to FIG. 14) of the first coilspring 12 formed into a hook shape is engaged (caught) so as to bemovable along the slope. A flat spring engagement surface 56 on whichthe spring proximal portion 12A of the first coil spring 12 is caught inan initial state before operation is formed on the top of the springmovement slope 55.

The two positioning convex portions 57 are provided at positionsopposite to each other across the central axis of the engagement plate50, and the engagement plate 50 can be interlocked with the operationcylinder 70 at a precise position by the positioning convex portionsbeing fitted into the positioning concave portions 75 of the operationunit cylinder 70.

As shown in FIGS. 2, 3, and 7, the plunger 90 is disposed so as to beinterposed between the engagement plate 50 and the operation unitproximal member 80. The plunger 90 includes a plunger flat plate portion91 that has a flat shape and is interposed between the engagement plate50 and the operation unit proximal member 80 and a plunger main bodyportion 92 that extends from a central portion of the plunger flat plateportion 91 in the distal direction.

A plunger interlocking convex portion 93 that extends from the centralportion in the proximal direction is formed on the plunger flat plateportion 91. The plunger interlocking convex portion 93 is inserted intoa plunger interlock hole 83 of the operation unit proximal member 80 tointerlock the plunger 90 with the operation unit proximal member 80.

The plunger main body portion 92 is a part that presses the gasket 21provided in a syringe 60 for discharging a liquid accommodated in thesyringe 60. The plunger main body portion 92 includes two plungerlocking projection portions 94 that restrict movement of the plunger 90with respect to a syringe cylinder 61 until a predetermined condition issatisfied, two movement amount restriction units 95 that restrictrotation of the structure 40 with respect to the operation unit 20 untila predetermined condition is satisfied, a plurality of resistanceprojection portions 96 (first contact portions) arranged in a directionalong the central axis of the plunger 90, and two movement preventionclaw portions 97 that prevent the structure 40 from being moved to thedistal side of the operation unit 20.

The two plunger locking projection portions 94 are parts that areprovided at positions opposite to each other across the central axis ofthe plunger 90 and can come into contact with a plunger locking inclinedportion 102 (refer to FIGS. 3 and 9) of the rotary cylinder proximalportion 100 to be described later. With the disposition of the plungerlocking inclined portion 102 on the distal side, the plunger lockingprojection portions 94 restrict movement of the plunger locking inclinedportion 102 in the proximal direction to restrict discharge of a liquidaccommodated in the syringe 60 due to the gasket 21 moving within thesyringe 60. When the plunger locking inclined portion 102 is rotated tomove from the distal side of the plunger locking projection portion 94,the plunger locking inclined portion 102 can be moved in the proximaldirection, and therefore, the liquid accommodated in the syringe 60 canbe discharged due to the gasket 21 moving within the syringe 60 (referto FIG. 15). That is, the plunger locking projection portion 94 and theplunger locking inclined portion 102 function as a plunger restrictionunit P that restricts the movement of the plunger 90 until apredetermined condition is satisfied and restricts the discharge of theliquid from the syringe 60.

The two movement amount restriction units 95 are provided at positionsopposite to each other across the central axis of the plunger 90 and areformed to have a predetermined length from the proximal end to thedistal end. The two movement amount restriction units 95 are formed witha sliding surface 98 (second contact portion) on which an attachmentportion 107 (refer to FIGS. 3 and 9) of the rotary cylinder proximalportion 100 to be described later is pressed by rotation of the rotarycylinder proximal portion 100 to be described later. The sliding surface98 holds the attachment portion 107 so as to be slidable in a statewhere the attachment portion 107 is pressed. An accommodation portion 99that receives the attachment portion 107 by allowing the rotation of theattachment portion so as to release the rotation restriction of theattachment portion 107 that has been moved in the proximal end bysliding on the sliding surface 98 is formed on the proximal side of themovement amount restriction unit 95. Accordingly, the movement amountrestriction unit 95 restricts the relative rotation of the structure 40and the operation unit 20 until the administration of a liquid iscompleted, the movement amount of the operation unit 20 with respect tothe structure 40 reaches a movement amount for the completion of theadministration, and the attachment portion 107 is received by theaccommodation portion 99. Note that the movement amount means a relativechange amount of the position of the structure, and specifically means achange amount of relative positions of the cover member 30 and thestructure 40 or a change amount of relative positions of the operationunit 20 and the structure 40, for example. The movement amount (changeamount) is not limited to being represented only by the relativemovement distance and includes at least one of the relative movementdistance and the relative rotary angle.

The plurality of resistance projection portions 96 are arranged atpositions opposite to each other across the central axis of the plunger90, laterally protrude, and connect between the plunger lockingprojection portion 94 and the movement amount restriction unit 95. Fourresistance projection portions 96 are symmetrically arranged atpositions opposite to each other across the central axis in a directionalong the central axis of the plunger 90, and the protruding height isset to be lower toward the proximal side of the resistance projectionportions 96. Note that the number of the resistance projection portions96 is not particularly limited.

The two movement prevention claw portions 97 are provided at positionsopposite to each other across the central axis of the plunger 90 andlaterally extend while inclining in the proximal direction. The movementprevention claw portions 97 are accommodated in the syringe 60 and cancome into contact with a distal end surface 106 (refer to FIGS. 3 and 9)of resistance claw portions 105 of the rotary cylinder proximal portion100 to be described later.

As shown in FIGS. 1 to 3 and 8, the cover member 30 includes acylindrical cover cylinder 31 and a planar cover distal portion 32 thatis formed so as to close an opening of the cover cylinder 31 on thedistal side. The cover member 30 is biased to the structure 40 in thedistal direction due to a biasing force of the second coil spring 11,and therefore, it is possible to move the needle tube 66 between aprotection position and an exposure position from which the needle tube66 is exposed.

Two second window portions 35 are formed in the cover cylinder 31 inorder to observe the inside of the syringe 60 from the outside. The twosecond window portions 35 are provided at positions opposite to eachother across the central axis of the cover cylinder 31 and are formedinto through-holes penetrating from the outer peripheral surface to theinner peripheral surface of the cover cylinder 31. Note that the secondwindow portions 35 may be formed of transparent material instead of thethrough-holes.

Two guiding ribs 33 extending in the axial direction and two separationprevention convex portions 34 are formed on the outer peripheral surfaceof the cover cylinder 31. The two guiding ribs 33 are provided atpositions opposite to each other across the central axis of the covermember 30 so as to protrude radially outward of the cover member and areaccommodated in the operation unit first grooves 73 (refer to FIG. 4) ofthe operation unit 20. Accordingly, the cover member 30 can relativelymove only in the axial direction without being relatively rotated withrespect to the operation unit 20. In addition, it is possible tosuppress rattling of the cover member 30 against the operation unit 20using the guiding rib 33 engaged with the operation unit first groove73.

The two separation prevention convex portions 34 are provided atpositions opposite to each other across the central axis of the covermember 30 so as to protrude radially outward from the cover member andare accommodated in operation unit second grooves 74 of the operationunit 20. The separation prevention convex portion 34 prevents the covermember 30 from being completely separated from the operation unit 20since the separation prevention convex portion 34 is caught in thepullout prevention rib 74A (refer to FIG. 4) of the operation unitsecond groove 74 when the operation unit 20 and the cover member 30 arerelatively separated along the axial direction.

Two safety convex portions 36 (first engagement portions) and twoguiding convex portions 37 are formed on the inner peripheral surface ofthe cover cylinder 31. The two safety convex portions 36 are provided atpositions opposite to each other across the central axis of the covermember 30 so as to protrude radially inward from the cover member andare accommodated in safety grooves 113 (refer to FIG. 10) of thestructure 40 to be described later. Each safety convex portion 36 isinterposed between slits 361 formed in the cover cylinder 31, andtherefore, is movable so as to be bent radially outward from the covercylinder.

The two guiding convex portions 37 are provided at positions opposite toeach other across the central axis of the cover member 30 so as toprotrude radially inward from the cover member and are accommodated in acam groove 112 (refer to FIG. 10) of the structure 40 to be describedlater. Each guiding convex portion 37 is interposed between the slits371 formed in the cover cylinder 31, and therefore, is movable so as tobe bent radially outward from the cover cylinder.

An opening portion 38 through which the needle tube 66 is passed in thedistal direction is formed on the central axis of the cover member 30 inthe cover distal portion 32 of the cover member 30.

As shown in FIGS. 2 and 3, the structure 40 is provided inside theoperation unit 20 and the cover member 30 so as to be relatively movablewith respect to the operation unit 20 and the cover member 30. Thestructure 40 includes the syringe 60, the rotary cylinder proximalportion 100 (intermediate housing) provided on the proximal side, andthe rotary cylinder distal portion 110 (lower housing) interlocked onthe distal side of the rotary cylinder proximal portion 100. The rotarycylinder proximal portion 100 and the rotary cylinder distal portion 110are rotatable around the central axis of the operation unit 20 and thecover member 30.

As shown in FIG. 2, the syringe 60 includes the cylindrical syringecylinder 61 capable of accommodating a liquid therein. The needle tube66 is attached to the distal end of the syringe cylinder 61.

A proximal end opening portion 63 is formed on a flange 62 on a proximalside of the syringe cylinder 61, and a discharge port 64 through which aliquid is passed is formed on the distal side of the syringe cylinder.The needle tube 66 is fixed to the distal end of the syringe cylinder 61such that the flow path inside the syringe communicates with thedischarge port 64 of the syringe 60, and a sharp needle tip is formed atthe distal end. The gasket 21 comes into contact with the distal portionof the plunger main body portion 92, and is disposed so as to beslidable along the axial direction of the syringe cylinder 61 whilemaintaining liquid-tightness by being brought into close contact with aninner wall surface 65 of the syringe cylinder 61. The liquid in thespace defined by the syringe cylinder 61 and the gasket 21 can bedischarged from the needle tube 66 through the discharge port 64 bymoving the inside of the syringe cylinder 61 in the distal directionusing the gasket 21 being pressed by the plunger main body portion 92.Although there is space between the plunger main body portion 92 and thegasket 21 that are interlocked only by contact therebetween the gasket21 is hardly rotated with respect to the plunger 90 due to frictionalforce acting thereon. Note that the gasket 21 and the plunger 90 may bestrongly interlocked with each other such that the gasket 21 is notrotatable with respect to the plunger 90. As the interlocking method,for example, attaching them together or interlocking one with another byproviding a convex portion in the distal portion of the plunger 90 andproviding a concave portion, into which the convex portion is fitted, inthe gasket 21 may be employed.

As shown in FIGS. 2, 3, and 9, the rotary cylinder proximal portion 100includes two noise generation holes 101 with which the noise generationclaws 82 (refer to FIG. 5) are engaged, two plunger locking inclinedportions 102 coming into contact with the plunger locking projectionportions 94, two rotary cylinder engagement claws 103 engaged with therotary cylinder distal portions 110, resistance claw portions 105 cominginto contact with the resistance projection portions 96, and a springengagement portion 108 with which a spring distal portion of the firstcoil spring 12 formed into a hook shape is engaged (caught).

The two noise generation holes 101 are formed at positions opposite toeach other across a central axis of the structure 40 and generate noiseby being engaged with the noise generation claws 82 formed on theoperation unit proximal member 80. The two plunger locking inclinedportions 102 are formed at positions opposite to each other across thecentral axis of the structure 40, and as shown in FIG. 3, the twoplunger locking inclined portions are positioned on the distal side ofthe plunger locking projection portions 94 formed in the plunger 90 inan initial state of the provision of the liquid administration device 10and restrict the movement of the plunger 90 in the distal direction torestrict the administration of a liquid. When the rotary cylinderproximal portion 100 is rotated with respect to the plunger 90 from thisstate, the plunger locking inclined portion 102 is deviated from theposition of the plunger locking projection portion 94 in the distaldirection and the restriction of the movement of the plunger 90 in thedistal direction is released, thereby enabling the administration of aliquid. That is, the plunger locking inclined portion 102 and theplunger locking projection portion 94 function as a plunger restrictionunit P that restricts the movement of the plunger 90 until apredetermined condition is satisfied.

The two rotary cylinder engagement claws 103 are formed at positionsopposite to each other across the central axis of the structure 40 andare engaged with rotary cylinder engagement holes 111 (refer to FIG. 10)formed in the rotary cylinder distal portions 110. The rotary cylinderproximal portion 100 and the rotary cylinder distal portions 110 areconstituted so as to be integrally moved by the rotary cylinderengagement claws 103 being engaged with the rotary cylinder engagementholes 111.

The proximal portion of the outer peripheral surface of the rotarycylinder proximal portion 100 is formed with a flange-shaped outerperipheral convex portion 104 protruding radially outward from therotary cylinder proximal portion.

The two resistance claw portions 105 are formed at positions opposite toeach other across the central axis of the structure 40 and protruderadially inward from the rotary cylinder proximal portion. The tworesistance claw portions 105 apply resistance force by beingsequentially brought into contact with the plurality of resistanceprojection portions 96 when the operation unit 20 moves to the rotarycylinder proximal portion 100 in the distal direction. The movementprevention claw portion 97 provided in the operation unit 20 can comeinto contact with the distal end surface 106 formed on the distal sideof the resistance claw portion 105 when the operation unit 20 is movedto the rotary cylinder proximal portion 100 in the proximal direction(refer to FIG. 2).

In addition, the attachment portion 107 that is a surface that restrictsrotation of the rotary cylinder proximal portion 100 with respect to theoperation unit 20 by being brought into contact with the sliding surface98, is formed on the resistance claw portion 105.

As shown in FIGS. 2, 3, 10, and 11, the two rotary cylinder engagementholes 111 with which the rotary cylinder engagement claws 103 (refer toFIG. 9) of the rotary cylinder proximal portion 100 are engaged, two camgrooves 112, and two safety grooves 113 are formed on the outerperipheral surface of the rotary cylinder distal portion 110.

The two rotary cylinder engagement holes 111 are formed at positionsopposite to each other across the central axis of the structure 40, andthe rotary cylinder engagement claws 103 formed in the rotary cylinderproximal portion 100 are engaged with the rotary cylinder engagementholes.

The two cam grooves 112 are formed at positions opposite to each otheracross the central axis of the structure 40, accommodate the guidingconvex portions 37 (refer to FIG. 8) of the cover member 30, andrelatively move the guiding convex portions 37 along the groove. Thatis, the cam groove 112 and the guiding convex portion 37 function as anoperation guide portion M that is constituted of a cam mechanismdefining relative movement of the structure 40 and the cover member 30.

The cam groove 112 includes an initial linear groove 112A that extendsalong the axial direction of the rotary cylinder distal portion 110 andis formed in a linear shape, an inclined groove 112B that is formed soas to be inclined in the axial direction of the rotary cylinder distalportion 110, and a linear groove 112C that extends along the axialdirection of the rotary cylinder distal portion 110 and is formed in alinear shape.

The initial linear groove 112A is formed so as to extend from the distalportion of the outer peripheral surface in the proximal direction. Astepped portion 114 that receives the guiding convex portion 37 so as tobe undetachable to the initial linear groove 112A is formed in thedistal portion of the initial linear groove 112A when assembling thedevice. The stepped portion 114 can guide the guiding convex portion 37to the initial linear groove 112A while making the guiding convexportion 37 slip along the slope 114A since the distal side thereof isformed so as to be inclined inside thereof. In addition, the steppedportion 114 is formed with a wall surface 114B that perpendicularlyrises at about 90 degrees with respect to the axial direction of therotary cylinder distal portion 110 on the proximal side and prevents theguiding convex portion 37, which has passed the proximal side of thestepped portion 114 through the slope 114A once, from being separated bypassing the wall surface 114B of the stepped portion 114 again.

The inclined groove 112B is formed to communicate with the proximalportion of the initial linear groove 112A and obliquely extends from theproximal portion of the initial linear groove 112A in the proximaldirection. The inclined groove 112B is formed to be shorter than oneturn.

A holding portion for suspension 112D is provided immediately in frontof a part of the inclined groove 112B communicating with the lineargroove 112C, and an edge for suspension 112E that is formed at an angleorthogonal to the axial direction of the rotary cylinder distal portion110 is formed at an edge on the distal side of the holding portion forsuspension 112D. The holding portion for suspension 112D is a part bywhich the guiding convex portion 37 of the cover member 30 is held whensuspending the administration. Note that the edge for suspension 112Emay not be formed at the angle orthogonal to the axial direction of therotary cylinder distal portion 110 and may be formed so as to beinclined from the initial linear groove 112A to the linear groove 112Cin the distal direction, that is, so as to be inclined in a reverseddirection of the inclination angle of the inclined groove 112B.

The linear groove 112C is formed to communicate with the proximalportion of the inclined groove 112B and extends from the proximalportion of the inclined groove 112B in the distal direction.

Note that the cam groove 112 may be formed in the cover member 30 andthe guiding convex portion 37 may be formed in the structure 40.

The two safety grooves 113 are formed at positions opposite to eachother across the central axis of the structure 40 and accommodate safetyconvex portions 36 of the cover member 30. The safety groove 113restricts the relative movement of the cover member 30 with respect tothe structure 40 in the axial direction in accordance with thepositional relationship between the structure 40 and the cover member 30that relatively move using the cam groove 112 and the guiding convexportion 37. Accordingly, after the movement amount of the cover member30 with respect to the structure 40 in the distal direction reaches apredetermined exposure restriction operation amount after the covermember 30 moves to the structure 40 in the proximal direction, that is,a living body is punctured with the needle tube 66 and theadministration of a liquid is completed, the safety groove 113 and thesafety convex portion 36 constitute an exposure restriction unit E(refer to FIG. 12(B)) that suppresses protruding of the needle tube 66due to the cover member 30 being moved back to the structure 40 in theproximal direction.

The safety groove 113 includes a first safety groove 113A that extendsin the axial direction of the rotary cylinder distal portion 110 and isformed in a linear shape, a second safety groove 113B that extends inparallel to the first safety groove 113A, and a proximal sidecommunication groove 113C in which the first safety groove 113A and thesecond safety groove 113B are communicated with each other in theproximal portion.

A safety stepped portion 115 (second engagement portion) that allowsmovement of the safety convex portion 36 in the distal direction butsuppresses movement thereof in the proximal direction is formed in thesecond safety groove 113B. The safety slope 115A on the proximal side isformed so as to be inclined from the inside of the second safety groove113B, and therefore, the safety stepped portion 115 can guide the safetyconvex portion 36 to the distal side while making the safety convexportion 36 slip along the safety slope 115A. In addition, the safetystepped portion 115 is formed with a safety wall surface 115B thatperpendicularly rises at about 90 degrees with respect to the axialdirection of the rotary cylinder distal portion 110 on the distal side,and thus, the safety convex portion 36 that has passed the safetystepped portion 115 in the distal direction through the safety slope115A once is engaged with the safety stepped portion 115, therebysuppressing the safety convex portion 36 from passing the safety steppedportion 115 in the proximal direction again.

When the guiding convex portion 37 is positioned in the initial lineargroove 112A in the operation guide portion M, the structure 40 and thecover member 30 enter a first state where the safety stepped portion 115and the safety convex portion 36 are not arranged on an identical axisparallel to a rotary axis. In the first state, the safety convex portion36 is positioned in the first safety groove 113A, and therefore, thereis no case where the safety stepped portion 115 and the safety convexportion 36 are engaged with each other even if the structure 40 and thecover member 30 relatively move in the axial direction. Then, when theguiding convex portion 37 is positioned in the holding portion forsuspension 112D, the structure 40 and the cover member 30 enter a secondstate where the relative rotation of the operation unit 20 and thestructure 40 is restricted by bringing the attachment portion 107 intocontact with the sliding surface 98. In addition, when the guidingconvex portion 37 is positioned in the linear groove 112C, the structure40 and the cover member 30 enter a third state where the safety steppedportion 115 and the safety convex portion 36 are arranged on anidentical axis parallel to the rotary axis. In the third state, thesafety convex portion 36 is positioned in the second safety groove 113Band the structure 40 and the cover member 30 relatively move in theaxial direction by a predetermined distance (exposure restrictionoperation amount), and therefore, the safety stepped portion 115 and thesafety convex portion 36 can be engaged with each other. Once the safetyconvex portion 36 moves to the distal side of the safety stepped portion115, the proximal end of the safety convex portion 36 comes into contactwith the safety wall surface 115B, and therefore, the safety convexportion 36 is suppressed from passing the safety stepped portion 115 inthe proximal direction.

Note that the safety groove 113 may be formed in the cover member 30 andthe safety convex portion 36 may be formed in the structure 40.

In addition, the rotary cylinder distal portion 110 includes a rotarycylinder extension 116 that extends in the proximal direction, a supportportion 118 that supports the syringe cylinder 61 so as to be relativelyrotatable, and a rotary-cylinder distal projection portion 119 thatprotrudes radially outward from the distal portion. The proximal portionof the rotary cylinder extension 116 is formed with a rotationrestriction unit 117 that comes into contact with the side surface ofthe flange 62 so as to restrict rotation of the syringe cylinder 61around the central axis in one direction. The rotation restriction unit117 plays a role of disposing the syringe cylinder 61 at a position in aproper rotational direction by being brought into contact with theflange 62 during the assembling. Note that the rotation restriction unit117 allows rotation of the syringe cylinder 61 around the central axisin a reversed direction without restricting the rotation.

The support portion 118 protrudes in the proximal direction so as toslidably come into contact with a distal surface 68 facing in the distaldirection of the syringe cylinder 61. The support portion 118 is formedin a ring shape by being divided into a plurality of parts so as tosurround the discharge port 64. Note that the support portion 118 maynot be divided into a plurality of parts. When the support portion isdivided into a plurality of parts, the contact area between the distalsurface 68 and the support portion 118 is reduced, and therefore, thesyringe cylinder 61 is easily made to be more slidable, which is morepreferable. The support portion 118 comes into contact with the distalsurface 68 at its protruding top and the contact area therebetween issmall, and therefore, it is possible to support the syringe cylinder 61so as to be slidable in the rotational direction. The protruding top ofthe support portion 118 may have a shape of which the contact area isreduced. The protruding top of the support portion 118 preferably has aspherical surface shape so that the syringe cylinder 61 becomes moreslidable, which is preferable. In a case where the support portion 118is divided into at least 3 points and has a circular shape when thedistal portion is seen from the proximal portion, and the protruding topthereof has a spherical surface shape, the syringe cylinder 61 becomesmore slidable, which is more preferable. Note that the surface cominginto contact with the support portion 118 may not be the distal surface68 as long as the surface coming into contact with the support portion118 faces the distal direction of the syringe cylinder 61.

At least one of the support portion 118 or the distal surface 68 may besubjected to surface treatment. The contact part can made to be slipperyand only the structure 40 can be made to be easily rotated by subjectingthe support portion 118 or the distal surface 68 to the surfacetreatment. Examples of the surface treatment include silicone coating.

When frictional force between the gasket 21 and the inside of thesyringe cylinder 61 is larger than frictional force between the supportportion 118 and the distal surface 68, the syringe cylinder 61 is fixedby the frictional force between the gasket 21 and the inside of thesyringe cylinder 61, and therefore, slidability with the support portion118 is improved.

The rotary-cylinder distal projection portion 119 is a part with which afixing hook 124 (refer to FIG. 24), to be described later, provided inthe cap 120 is interlocked and is formed on a portion in thecircumferential direction. In an initial state before theadministration, the rotary-cylinder distal projection portion 119 doesnot exist at the position provided with the fixing hook 124.Accordingly, the fixing hook 124 is not interlocked with therotary-cylinder distal projection portion 119, and therefore, it ispossible to remove the cap 120 from the cover member 30. Aftercompletion of the administration, unlike the initial state, therotary-cylinder distal projection portion 119 exists at the positionwith which the fixing hook 124 can be interlocked since the rotarycylinder distal portion 110 is rotated with respect to the cover member30, and therefore, the fixing hook 124 can be interlocked with therotary-cylinder distal projection portion 119 so as to be caughttherein.

As shown in FIGS. 2 and 3, the second coil spring 11 is disposed insidethe cover member 30, and the distal portion of the second coil springcomes into contact with a proximal surface of the cover distal portion32 and the proximal portion of the second coil spring comes into contactwith the structure 40. The second coil spring 11 is disposed in a stateof being contracted in the axial direction. Accordingly, the covermember 30 is biased to the structure 40 in the distal direction.

As shown in FIG. 2, the first coil spring 12 is disposed inside theoperation unit 20 and generates force of moving the operation unit 20 tothe syringe 60 in the distal direction. The first coil spring 12 is in astate where the coil is contracted in a natural state free from externalforce. In a state where the first coil spring is forcefully stretched,the hook-shaped spring distal portion is interlocked with the springengagement portion 108 of the structure 40, and the hook-shaped springproximal portion 12A (refer to FIG. 14) is interlocked with the springengagement portion 54 of the engagement plate 50 so as to be caughttherein by penetrating the engagement claw insertion hole 53 of theengagement plate 50. Accordingly, the first coil spring 12 functions asan auxiliary mechanism when generating the force of moving the operationunit 20 to the structure 40 in the distal direction and discharging aliquid from the syringe 60 through the needle tube 66.

As shown in FIGS. 2 and 24, the cap 120 is installed so as to cover thecover member 30 from the outside in an unused condition in whichoperation of administering the liquid has not been performed. The cap isa member formed in a bottomed cylindrical shape, and includes aplate-shaped bottom portion 121, a cylindrical cap cylinder 122 thatrises from the bottom portion 121, and two fixing hooks 124 that extendfrom the bottom portion 121 in the proximal direction. A cap 123 for aneedle tube that covers the needle tube 66 is fixed to the bottomportion 121.

Constituent materials for the cover member 30, the engagement plate 50,the syringe 60, the operation unit cylinder 70, the operation unitproximal member 80, the plunger 90, the rotary cylinder proximal portion100, the rotary cylinder distal portion 110, and the cap 120 are notparticularly limited, and examples thereof include various types ofresins such as polycarbonate, polyvinyl chloride, polyethylene,polypropylene, cyclic polyolefin, polystyrene, poly-(4-methylpentene-1),polyesters such as polyethylene terephthalate and polyethylenenaphthalate, butadiene-styrene copolymers, and polyamide (for example,nylon 6, nylon 6-6, nylon 6-10 and nylon 12).

The constituent material of the gasket 21 and the cap 123 for a needletube is preferably an elastic material, but is not particularly limited.Examples thereof include various rubber materials such as naturalrubber, butyl rubber, isoprene rubber, butadiene rubber,styrene-butadiene rubber, and silicone rubber; various types ofthermoplastic elastomers such as polyurethane, polyester, polyamide,olefin, and styrene elastomers; or mixtures thereof.

The constituent material of the needle tube 66 is not particularlylimited, and examples thereof include metallic materials such asstainless steel, aluminum or aluminum alloys, and titanium or titaniumalloys.

The constituent materials of the second coil spring 11 and the firstcoil spring 12 are not particularly limited, and examples thereofinclude metallic materials such as stainless steel or copper.

Next, the usage of the liquid administration device 10 according to thefirst embodiment will be described.

First, as shown in FIGS. 1 to 3, the liquid administration device 10 inan initial unused state is prepared, and the cap 120 that covers thecover member 30 and the needle tube 66 is removed to set the liquidadministration device to an initial state. Force is applied in adirection in which the structure 40 falls off from the operation unit 20when removing the cap 120. However, it is possible to prevent thestructure 40 from falling off from the operation unit 20 by bringing themovement prevention claw portion 97 that is provided in the operationunit 20 into contact with the distal end surface 106 of the resistanceclaw portion 105.

In the initial state, a liquid is accommodated inside the syringecylinder 61, the operation unit 20 is positioned in the proximaldirection with respect to the structure 40, and the first coil spring 12enters a state of being extended. The spring proximal portion 12A of thefirst coil spring 12 is interlocked so as to be caught in a flat springengagement surface 56 of the engagement plate 50. Furthermore, the covermember 30 is biased to the structure 40 in the distal direction by thesecond coil spring 11.

In the initial state, the rotation restriction unit 117 formed in therotary cylinder distal portion 110 comes into contact with the sidesurface of the flange 62 to restrict rotation of the syringe cylinder 61around the central axis in one direction, and to allow rotation of thesyringe cylinder in a reversed direction.

In the operation guide portion M, as shown in FIG. 12(A), the guidingconvex portion 37 of the cover member 30 is positioned in the initiallinear groove 112A of the rotary cylinder distal portion 110 so as to bemovable along the initial linear groove 112A in the axial direction. Inaddition, as shown in FIG. 12(B), in the exposure restriction unit E,the safety convex portion 36 of the cover member 30 is positioned in thefirst safety groove 113A of the structure 40 so as to be movable alongthe first safety groove 113A in the axial direction. For this reason,the cover member 30 enters a state of being movable to the structure 40in the proximal direction. Then, the cover member 30 and the structure40 enter a first state where the safety convex portion 36 and the safetystepped portion 115 are not arranged on an identical axis parallel tothe rotary axis.

In addition, as shown in FIG. 3, in the plunger restriction unit P, theplunger locking inclined portion 102 formed in the rotary cylinderproximal portion 100 is positioned on the distal side of the plungerlocking projection portion 94 formed in the plunger 90 to restrictmovement of the plunger 90 in the distal direction and to restrictunexpected administration of a liquid. In addition, the resistance clawportion 105 does not come into contact with the resistance projectionportion 96.

In addition, the attachment portion 107 of the rotary cylinder proximalportion 100 is positioned away from the sliding surface 98 of themovement amount restriction unit 95 without being brought into contactwith the sliding surface.

Next, the operation unit 20 is gripped and the cover distal portion 32of the cover member 30 is abutted on a living body. When the coverdistal portion 32 of the cover member 30 is pressed to the living body,the cover member 30 enters a state of being movable to the structure 40in the proximal direction, and therefore, as shown in FIGS. 13 to 15,the cover member 30 moves to the structure 40 in the proximal directionwhile contracting the second coil spring 11. Accordingly, the needletube 66 protrudes from the cover member 30 in the distal direction andenters a state in which the living body is punctured with the needletube. Note that, as shown in FIG. 15, the movement of the plunger 90 tothe syringe cylinder 61 is restricted due to the plunger lockinginclined portion 102 coming into contact with the plunger lockingprojection portion 94, and therefore, a liquid is not administered.

When the cover member 30 moves to the structure 40 in the proximaldirection, as shown in FIG. 13(A), in the operation guide portion M, theguiding convex portion 37 of the cover member 30 is positioned in theproximal portion of the initial linear groove 112A of the structure 40,that is, on the distal side of the inclined groove 112B. In addition, asshown in FIG. 13(B), in the exposure restriction unit E, the safetyconvex portion 36 of the cover member 30 is positioned in the proximalportion of the first safety groove 113A of the structure 40, and is setto be movable to the proximal side communication groove 113C.

Next, when the operation unit 20 is further pressed, as shown in FIGS.16(A) and 17, the guiding convex portion 37 that has reached theinclined groove 112B presses the inclined groove 112B. Therefore, theguiding convex portion 37 moves in the inclined groove 112B, and thestructure 40 is rotated with respect to the operation unit 20 and thecover member 30. When the structure 40 is rotated and the attachmentportion 107 comes into contact with the sliding surface 98, furtherrotation is suppressed, and the guiding convex portion 37 enters thesecond state of stopping in the holding portion for suspension 112Dwithout reaching the linear groove 112C. When the structure 40 isrotated with respect to the operation unit 20 and the cover member 30,the resistance claw portion 105 does not come into contact with theresistance projection portion 96. Therefore, there is no case where therotation is interrupted by the contact between the resistance clawportion 105 and the resistance projection portion 96, and favorableoperation can be achieved.

As shown in FIG. 16(B), in the exposure restriction unit E, the safetyconvex portion 36 stops immediately before the safety convex portionreaches the second safety groove 113B through the proximal sidecommunication groove 113C by the rotation of the structure 40. At thistime, the syringe cylinder 61 is supported by the support portion 118provided in the structure 40 so as to be relatively rotatable.Therefore, the syringe cylinder 61 is not rotated together with thestructure 40 even if the structure 40 is rotated and is maintained to benon-rotational with respect to the operation unit 20 due to thefrictional force between the syringe cylinder 61 and the gasket 21 thatis non-rotationally interlocked with the plunger 90. For this reason,the needle tube 66 connected to the syringe cylinder 61 is also notrotated, and therefore, it is possible to secure safety during thepuncturing.

In the plunger restriction unit P, as shown in FIG. 17, the plungerlocking inclined portion 102 is deviated from the position of theplunger locking projection portion 94 in the distal direction by therotation of the structure 40 with respect to the operation unit 20, andthe restriction of the movement of the plunger 90 in the distaldirection is released, and therefore, it is possible to administer aliquid.

In addition, with the rotation of the structure 40 with respect to theoperation unit 20, the hook-shaped spring proximal portion 12A is movedfrom the spring engagement surface 56 to the spring movement slope 55 toslip along the spring movement slope 55 and is moved so as to be rotatedaround the central axis of the operation unit 20 in the circumferentialdirection. Accordingly, it is possible to prevent the operability of theliquid administration device 10 from being impaired by suppressinggeneration of torsion of the first coil spring 12 that can occur due tothe rotation of the structure 40 and suppressing unnecessary forceapplied on the liquid administration device 10.

Next, when the operation unit 20 is further pressed, the guiding convexportion 37 of the cover member 30 cannot further move within the camgroove 112 in the proximal direction since the attachment portion 107 isbrought into contact with the sliding surface 98. Therefore, the covermember 30 cannot further move to the structure 40 in the proximaldirection. For this reason, the operation unit 20 moves to the structure40 and the cover member 30 in the distal direction, and as shown in FIG.18, the gasket 21 moves inside the syringe cylinder 61 and a liquid isadministered to a living body through the needle tube 66. At this time,as shown in FIG. 16(A), in the operation guide portion M, the covermember 30 does not move to the structure 40, and therefore, the guidingconvex portion 37 does not move and is positioned at the holding portionfor suspension 112D of the inclined groove 112B. As shown in FIG. 16(B),also in the exposure restriction unit E, the safety convex portion 36does not move and is positioned at a position immediately before thesafety convex portion reaches the second safety groove 113B of theproximal side communication groove 113C.

In addition, administration of the liquid advances and the attachmentportion 107 slides and moves on the sliding surface 98. As shown in FIG.18, the resistance claw portion 105 climbs over the resistanceprojection portions 96, which are arranged in the axial direction, whilecoming into contact with the resistance projection portions. In a regionbetween two resistance projection portions 96 that is provided with noresistance projection portion 96, the resistance claw portion moveswithout being brought into contact with the resistance projectionportions 96. When the resistance claw portion 105 climbs over theresistance projection portions 96, resistance force is generated by theresistance claw portion 105 and the resistance projection portions 96being deformed.

The resistance claw portion 105 and the resistance projection portions96 are symmetrically disposed across the central axis, and therefore,reaction forces generated in the direction orthogonal to the centralaxis are canceled by each other and only the force parallel to themovement direction remains. Accordingly, unnecessary force is notapplied on the liquid administration device 10, and favorable operationcan be achieved.

When the operation unit 20 moves to the structure 40 in the distaldirection, the first coil spring 12 functions as a discharge mechanismwhen generating force moving the operation unit 20 to the structure 40in the distal direction and discharging a liquid from the syringe 60through the needle tube 66 and as an auxiliary mechanism that supportsthe discharging.

The force that is applied for moving the gasket 21 in the syringecylinder 61 in the distal direction is set to be the sum of biasingforce (shrinkage force) F1 of the first coil spring 12, biasing force(expansive force) F2 of the second coil spring 11, and pressing force F4of a user. Force against the force is set to be the sum of liquiddischarge resistance F0, which is the sum of dynamic frictional forcebetween the inner wall surface of the syringe cylinder 61 and the gasket21 and needle tube discharge resistance for discharging a liquid in thesyringe cylinder 61 from the needle tube 66; and contact resistance F3when the resistance claw portion 105 comes into contact with theresistance projection portions 96. Note that the contact resistance F3is generated only when the resistance claw portion 105 comes intocontact with the resistance projection portion 96. Therefore, it isnecessary to apply the pressing force F4 such that the followingexpression (1) is provided when the resistance claw portion 105 does notcome into contact with the resistance projection portion 96, and thefollowing expression (2) is provided when the resistance claw portioncomes into contact with the resistance projection portion.

F1+F2+F4>F0  Expression (1)

F1+F2+F4>F0+F3  Expression (2)

Next, when the pressing of the operation unit 20 is released in order totemporarily stop the administration of a liquid in the middle of theadministration, the cover member 30 receives force with respect to thestructure 40 in the distal direction due to the biasing force F1 of thefirst coil spring 12, and the guiding convex portion 37 comes intocontact with the edge for suspension 112E of the holding portion forsuspension 112D as shown in FIG. 19(A). Accordingly, the cover member 30moves only by the movement amount of the guiding convex portion 37 inthe holding portion for suspension 112D in the axial direction and doesnot cover the needle tube 66. For this reason, when the cover member 30moves to the structure 40 in the distal direction, the exposurerestriction unit E that controls the needle tube 66 from protruding dueto the cover member 30 moving again to the structure 40 in the proximaldirection is not operated. Therefore, it is possible to start theadministration again even if the liquid administration device 10 isseparated from the living body. Moreover, even when the pressing of theoperation unit 20 is mistakenly released in the middle of theadministration, the cover member 30 hardly moves, and therefore, it ispossible to prevent the administration from being difficult due to theneedle tube 66 being pulled out from the living body due to the movementof the cover member 30, thereby improving the operability. In addition,when the guiding convex portion 37 comes into contact with the edge forsuspension 112E of the holding portion for suspension 112D by releasingthe pressing of the operation unit 20, the biasing force of the secondcoil spring 11 is received by the engaged part between the guidingconvex portion 37 and the holding portion for suspension 112D. As aresult, the second coil spring 11 cannot be expanded. For this reason,the movement of the cover member 30 is restricted and the biasing forceF2 of the second coil spring 11 is not applied to the movement of thegasket 21. Therefore, even a user with weak pressing force can operatethe device without any burden with a small amount of force that pushesthe operation unit 20. Note that the edge for suspension 112E is formedat an angle orthogonal to the axial direction of the rotary cylinderdistal portion 110, or is formed so as to be inclined in a reverseddirection of the inclination angle of the inclined groove 112B.Therefore, it is possible to prevent the guiding convex portion 37 fromreturning to the initial linear groove 112A due to the inclination ofthe inclined groove 112B and favorably maintain the state in which theadministration is suspended as it is. Moreover, as shown in FIG. 19(B),also in the exposure restriction unit E, the safety convex portion 36hardly moves and is positioned at a position immediately before thesafety convex portion reaches the second safety groove 113B of theproximal side communication groove 113C.

After a user stops the pressing of the operation unit 20 in the distaldirection, the biasing force F2 of the second coil spring 11 and thepressing force F4 of the user are not applied to the movement of thegasket 21. Therefore, when the resistance claw portion 105 does not comeinto contact with the resistance projection portion 96, a liquid isautomatically administered by the biasing force F1 of the first coilspring 12, and when the resistance claw portion 105 comes into contactwith the resistance projection portion 96, the contact resistance F3becomes greater and the administration of the liquid stops. In thiscase, it is necessary to satisfy the following expressions (3) and (4).

F1>F0  Expression (3)

F1≦F0+F3  Expression (4)

The biasing force F1 of the first coil spring 12 becomes smaller as theadministration advances and the first coil spring 12 is contracted.Accordingly, the contact resistance F3 becomes smaller as the pluralityof resistance projection portions 96 coming into contact with theresistance claw portion 105 are gradually reduced in size toward theproximal direction. Therefore, it is possible to set both theexpressions (3) and (4) so as to be always established from the start ofthe administration of a liquid to the end of the administration of aliquid.

As described above, when a user stops the pressing of the operation unit20 in the distal direction, the administration of a liquid is stopped bythe resistance claw portion 105 coming into contact with the resistanceprojection portion 96. Accordingly, it is possible to prevent a liquidfrom being automatically administered without pressing the operationunit 20 in the distal direction by the user when administering theliquid. Accordingly, it is possible to administer a liquid by theintention of the user. For example, it is possible to administer aliquid at a pace of the user, or it is possible to suspend theadministration of a liquid by stopping the pressing when it is necessaryto suspend the administration of the liquid.

Note that it is possible to stop the administration of a liquid in bothcases where the resistance claw portion 105 comes into contact with theresistance projection portion 96 or does not come into contact with theresistance projection portion, after a user stops the pressing of theoperation unit 20 in the distal direction. In this case, it is necessaryto satisfy the following expressions (5) and (6) instead of theexpressions (3) and (4).

F1≦F0  Expression (5)

F1≦F0+F3  Expression (6)

In addition, the device may also be set such that the administration ofa liquid is continued in both cases where the resistance claw portion105 comes into contact with the resistance projection portion 96 or doesnot come into contact with the resistance projection portion, after auser stops the pressing of the operation unit 20 in the distaldirection. In this case, it is necessary to satisfy the followingexpressions (7) and (8) instead of the expressions (3) and (4).

F1>F0  Expression (7)

F1>F0+F3  Expression (8)

In a case where the administration of a liquid temporarily stops, whenthe operation unit 20 is gripped again and a living body is puncturedwith the needle tube 66 to press the operation unit 20 in the distaldirection, the guiding convex portion 37 of the cover member 30 cannotmove from the holding portion for suspension 112D as shown in FIG. 20since the attachment portion 107 is brought into contact with thesliding surface 98. For this reason, the operation unit 20 moves to thestructure 40 and the cover member 30 in the distal direction and thegasket 21 moves inside the syringe cylinder 61 to administer a liquid toa living body through the needle tube 66.

Moreover, it is possible to repeat the above-described stopping andrestarting of the administration of a liquid plural times in accordancewith the situation. Meanwhile, it is possible to intentionally performthe administration to different areas by being divided into pluraltimes.

When the liquid inside the syringe cylinder 61 is absent and theadministration of the liquid is completed, as shown in FIG. 21, thenoise generation claw 82 provided in the operation unit 20 is engagedwith the noise generation hole 101 provided in the structure 40. Whenthe noise generation claw 82 is engaged with the noise generation hole101, the elastically deformed noise generation claw 82 is engaged withthe noise generation hole 101 in a manner of being returned to itsoriginal shape, and the noise generation claw 82 comes into contact withthe rotary cylinder proximal portion 100 formed with the noisegeneration hole 101 to generate noise. It is possible to acousticallycheck the completion of the administration of a liquid through thegeneration of noise.

When the movement amount of the operation unit 20 with respect to thestructure 40 reaches a movement amount for the completion of theadministration and the administration of a liquid is completed, thesliding surface 98 sliding on the attachment portion 107 reaches theaccommodation portion 99. When the sliding surface 98 reaches theaccommodation portion 99, the attachment portion 107 does not come intocontact with the sliding surface 98, and the restriction due to themovement amount restriction unit 95 is released. Therefore, thestructure 40 can rotate with respect to the operation unit 20.Accordingly, as shown in FIG. 22(A), the guiding convex portion 37 movesin the inclined groove 112B and reaches the linear groove 112C, and thestructure 40 is rotated with respect to the operation unit 20.Therefore, the resistance claw portion 105 having the attachment portion107 is accommodated in the accommodation portion 99. When the structure40 is rotated with respect to the operation unit 20, the resistance clawportion 105 is not already brought into contact with the resistanceprojection portion 96, and therefore, the rotation is not interrupted.When the resistance claw portion 105 is accommodated in theaccommodation portion 99, the movement amount restriction unit 95 ispositioned on the distal side of the resistance claw portion 105, andtherefore, it is possible to prevent the structure 40 from being pulledout from the operation unit 20 in the distal direction.

In a state where the administration is completed, in the exposurerestriction unit E, the safety convex portion 36 is positioned in theproximal portion of the second safety groove 113B as shown in FIG.22(B). At this time, the cover member 30 and the structure 40 enter thethird state where the safety convex portion 36 and the safety steppedportion 115 are arranged on an identical axis parallel to the rotaryaxis.

From this state, when the operation unit 20 is gripped and the coverdistal portion 32 is separated from the skin, as shown in FIG. 23, thecover member 30 moves to the structure 40 in the distal direction due tothe biasing force of the second coil spring 11, and the needle tube 66is accommodated in the cover member 30. Accordingly, as shown in FIG.23(A), the guiding convex portion 37 moves in the linear groove 112C inthe proximal direction. In the exposure restriction unit E, as shown inFIG. 23(B), the safety convex portion 36 moves in the second safetygroove 113B in the distal direction and is deformed and climbs over thesafety slope 115A of the safety stepped portion 115 while slipping alongthe safety slope thereof to reach the distal portion of the safetystepped portion 115. The movement amount at this time corresponds to anexposure restriction operation amount when the cover member 30 isshifted from the exposure position to the protection position. Once thesafety convex portion 36 climbs the safety stepped portion 115, themovement of the safety convex portion 36 in the proximal direction inthe second safety groove 113B is suppressed by the safety wall surface115B. Therefore, the cover member 30 cannot move to the structure 40 inthe proximal direction and enters a state where the exposure restrictionunit E is operated. When the cover member enters the state where theexposure restriction unit E is operated, the needle tube 66 cannotprotrude from the cover member 30 again, and therefore, it is possibleto improve safety by suppressing erroneous puncturing due to the needletube 66.

Thereafter, as shown in FIG. 24, the cap 120 is attached to the covermember 30. At this time, unlike the initial state, the rotary cylinderdistal portion 110 is rotated with respect to the cover member 30.Therefore, the fixing hook 124 of the cap 120 is caught in therotary-cylinder distal projection portion 119 of the rotary cylinderdistal portion 110 and the cap 120 is undetachably attached to therotary-cylinder distal projection portion, thereby securing safety.

As described above, the liquid administration device 10 according to thefirst embodiment is used for administering a liquid into a living body,and includes a structure 40 that includes a syringe 60 (accommodationbody) capable of accommodating the liquid therein and a needle tube 66communicatable with the inside of the syringe 60, an operation unit 20for discharging the liquid inside the syringe 60 from the needle tube 66by moving to the structure 40 in a distal direction, a cover member 30that is movable between a protection position at which the needle tube66 is covered and an exposure position from which the needle tube 66 isexposed, a first coil spring 12 (first biasing member) that biases theoperation unit 20 to the structure 40 in the distal direction, and asecond coil spring 11 (second biasing member) that biases the covermember 30 in the distal direction. The operation unit 20 and thestructure 40 have a resistance projection portion 96 (first contactportion) and a resistance claw portion 105 (second contact portion) thatapply pressing force to each other while changing a contact positionwhen the operation unit 20 moves to the structure 40 in the distaldirection. In this manner, the liquid administration device 10 isprovided with the resistance projection portion 96 and the resistanceclaw portion 105 that come into contact with each other while applyingthe pressing force to each other. Therefore, it is possible to impartthe contact resistance F3 against the biasing force F1 of the first coilspring 12 to the resistance projection portion and the resistance clawportion, and it is possible to suspend the administration by stoppingthe pressing of the operation unit 20 when it is necessary totemporarily suspend the administration. In addition, with the provisionof the resistance projection portion 96 and the resistance claw portion105, it is possible to arbitrarily set the contact resistance F3, andtherefore, the flexibility of design is improved. For example, it iseasy to design the device so as to satisfy desirable conditions such asadministering rate or suspension of the administration.

In addition, in the liquid administration device 10 according to thefirst embodiment, the structure 40 is relatively rotatable with respectto the operation unit 20 and the cover member 30. Therefore, arrangementcan be made such that a plurality of functions, such as theabove-described movement amount restriction unit 95, the exposurerestriction unit E that restricts exposure of the needle tube 66 afterthe administration, and the plunger restriction unit P that restrictsthe plunger 90 so as not to be pressed until a condition is satisfied,are operated at different rotational positions, and thus, the functionsdo not interfere with each other. When the structure is constituted soas not to be rotated with respect to the operation unit and the covermember, the device can be devised such that one member climbs overanother member while the members are brought into contact with eachother so as not to operate a function depending on the conditions inorder to exhibit all functions on linear motion. However, in this case,there are concerns that operability may deteriorate due to increasedresistance when pressing the operation unit and the accuracy of eachfunction may decrease. In contrast, since the structure 40 is relativelyrotatable with respect to the operation unit 20 and the cover member 30as in the present embodiment, it is possible to provide a plurality offunctions without interfering with each other. Therefore, it is possibleto improve the operability by reducing the resistance when pressing theoperation unit 20 and to improve the accuracy of each function.

In addition, in the liquid administration device 10 according to thepresent embodiment, the cover member 30 exists at a protection positionat which the needle tube 66 is covered in an initial state, andtherefore, it is possible to reduce fear when inserting the needle tube66 before injecting a drug solution. Moreover, it is possible torestrict re-exposure of the needle tube 66 being pulled out in themiddle of operation by covering the needle tube 66 with the cover member30, and to reduce mental pain in which the expensive medicine cannot beused for injection again.

In addition, the liquid administration device 10 can be smoothlyoperated through rotary motion using the relationship between the grooveand the convex portion and can be operated with weak force, therebyfacilitating the administration. Note that, in the case of the linearmotion, it is difficult to obtain the same effect as that in the presentinvention with a small amount of force on the assumption that there is astep over which it is necessary to climb as described above.

In addition, the resistance projection portion 96 (first contactportion) and the resistance claw portion 105 (second contact portion)intermittently come into contact with each other when the operation unit20 moves to the structure 40 in the distal direction, and therefore, itis possible to generate the contact resistance F3 only when they comeinto contact with each other. For this reason, for example, it ispossible to set the administration so as to be suspended by stopping thepressing only when the resistance projection portion 96 and theresistance claw portion 105 come into contact with each other whileproviding desirable conditions such as administering rate when theresistance projection portion and the resistance claw portion do notcome into contact with each other.

In addition, the contact resistance F3 between the resistance projectionportion 96 (first contact portion) and the resistance claw portion 105(second contact portion) changes when the operation unit 20 moves to thestructure 40 in the distal direction. Therefore, it is possible to setthe contact resistance F3 desirable for administering rate, suspensionof the administration, or the like depending on the position of theoperation unit 20 with respect to the structure 40.

In addition, the biasing force F1 due to the first coil spring 12 (firstbiasing member) becomes smaller as the operation unit 20 moves to thestructure 40 in the distal direction and the contact resistance F3between the resistance projection portion 96 (first contact portion) andthe resistance claw portion 105 (second contact portion) becomes smalleras the operation unit 20 moves to the structure 40 in the distaldirection. Therefore, the contact resistance F3 is reduced in responseto the decrease of the biasing force F1 of the first coil spring 12. Forthis reason, it is possible to reduce the influence of the decrease ofthe biasing force of the first coil spring 12 on the administering rateor the suspension of the administration, using the contact resistanceF3.

In addition, if the difference between the contact resistance F3 and thebiasing force F1 due to the first coil spring 12 (first biasing member)is maintained to be constant when the operation unit 20 moves to thestructure 40 in the distal direction, it is possible to maintain theadministering rate to be constant under all of the conditions from thestart of the administration to the completion of the administration andto administer a liquid at a constant administering rate using constantpressing force. Therefore, it is possible to improve accuracy and safetyof the administration.

In addition, at least two (two in the embodiment) resistance projectionportions 96 (first contact portions) and at least two (two in theembodiment) resistance claw portions 105 (second contact portion) areprovided, and pressing forces generated by each contact are constitutedto be canceled by each other in a direction along a plane orthogonal tothe movement direction of the operation unit 20 to the structure 40.Therefore, only the force in the movement direction remains, andunnecessary force is hardly applied to the liquid administration device10. Thus, favorable operation can be achieved.

In addition, The structure 40 is rotatable with respect to the operationunit 20, and the resistance projection portion 96 (first contactportion) and the resistance claw portion 105 (second contact portion) donot come into contact with each other when the structure 40 is rotatedwith respect to the operation unit 20. Therefore, the rotation of thestructure is not interrupted by the contact between the resistanceprojection portion 96 and the resistance claw portion 105, and thus,favorable operation can be achieved.

Second Embodiment

A liquid administration device 150 according to a second embodiment isdifferent from the liquid administration device according to the firstembodiment only in that the movement amount restriction unit 95 thatrestricts the movement amount of the cover member 30 is not provided.Note that parts having identical functions as those in the liquidadministration device 10 according to the first embodiment areidentified by the same reference numerals throughout and the detaileddescriptions are not repeated in order to avoid repetition.

As shown in FIG. 25, in a plunger 160 of the liquid administrationdevice 150 according to the second embodiment, the plunger 160 may notbe provided with the movement amount restriction unit 95 that restrictsthe movement amount by which the cover member 30 is movable to thestructure 40 in the distal direction so as not to reach an exposurerestriction operation amount until the administration is completed. Inthis case, the device enters the third state from the first statewithout passing through the second state, and the administrationoperation is performed in the third state.

Specifically, similarly to the first embodiment, when the operation unit20 is pressed and the cover member 30 brought into contact with the skinmoves to the structure 40 in the proximal direction, as shown in FIG.26(A), in the operation guide portion M, the guiding convex portion 37of the cover member 30 moves to the proximal portion of the initiallinear groove 112A of the structure 40. Then, the guiding convex portionmoves along an inclination of the inclined groove 112B and is positionedin the proximal portion of the linear groove 112C. When the guidingconvex portion 37 moves to the proximal portion of the linear groove112C through the inclined groove 112B from the initial linear groove112A, the structure 40 is rotated with respect to the operation unit 20and the cover member 30. Accordingly, as shown in FIG. 26(B), in theexposure restriction unit E, the safety convex portion 36 reaches theproximal portion of the second safety groove 113B through the proximalside communication groove 113C from the first safety groove 113A. Atthis time, the cover member 30 and the structure 40 enter the thirdstate where the safety convex portion 36 and the safety stepped portion115 are arranged on an identical axis parallel to the rotary axis.

Next, when the operation unit 20 is further pressed, the guiding convexportion 37 of the cover member 30 cannot further move within the camgroove 112 in the proximal direction, and therefore, the cover member 30cannot further move to the structure 40 in the proximal direction. Then,the operation unit 20 moves to the structure 40 and the cover member 30in the distal direction, and the gasket 21 moves inside the syringecylinder 61 and a liquid is administered to a living body through theneedle tube 66. At this time, in the operation guide portion M, thecover member 30 does not move to the structure 40, and therefore, theguiding convex portion 37 does not move and is positioned in theproximal portion of the linear groove 112C. Also in the safety mechanism(in the exposure restriction unit E), the safety convex portion 36 doesnot move and is positioned in the proximal portion of the second safetygroove 113B.

During the administration, similarly to the first embodiment, theresistance claw portion 105 climbs over resistance projection portions96 that are arranged in the axial direction while coming into contactwith the resistance projection portions. In a region between tworesistance projection portions 96 that is provided with no resistanceprojection portion 96, the resistance claw portion moves without beingbrought into contact with the resistance projection portions 96. Whenthe resistance claw portion 105 climbs over the resistance projectionportions 96, resistance force is generated by the resistance clawportion 105 and the resistance projection portions 96 being deformed.

After the administration of a liquid is completed, when the operationunit 20 is gripped and the cover distal portion 32 is separated from theskin, as shown in FIG. 27, the cover member 30 moves to the structure 40in the distal direction due to the biasing force of the second coilspring 11, and the needle tube 66 is accommodated in the cover member30. In the operation guide portion M, as shown in FIG. 27(A), theguiding convex portion 37 moves to the distal portion in the lineargroove 112C. In addition, as shown in FIG. 27(B), in the exposurerestriction unit E, the safety convex portion 36 moves in the secondsafety groove 113B in the distal direction and reaches the safetystepped portion 115 on the distal side. Once the safety convex portion36 climbs the safety stepped portion 115, the cover member 30 cannotmove to the structure 40 in the proximal direction and the needle tube66 cannot protrude from the cover member 30 again, thereby securingsafety.

As described above, also in the liquid administration device 150according to the second embodiment, the resistance projection portion 96and the resistance claw portion 105 that come into contact with eachother while applying the pressing force to each other are provided.Therefore, it is possible to impart the contact resistance F3 againstthe biasing force F1 of the first coil spring 12 to the resistanceprojection portion and the resistance claw portion, and it is possibleto suspend the administration by stopping the pressing of the operationunit 20 when it is necessary to temporarily suspend the administration.In addition, with the provision of the resistance projection portion 96and the resistance claw portion 105, it is possible to arbitrarily setthe contact resistance F3, and therefore, the flexibility of design isimproved. For example, it is easy to design the device so as to satisfydesirable conditions such as administering rate or suspension of theadministration.

Note that the present invention is not limited only to theabove-described embodiments, and various modifications can be made bythose skilled in the art within technical ideas of the presentinvention. For example, as shown in a modification example of the firstembodiment shown in FIG. 28, a part of a plunger 170 that comes intocontact with the resistance claw portion 105 may be a flat contactsurface 171 (first contact portion) instead of being a projection shape.It is possible to arbitrarily change contact resistance F3 with respectto the resistance projection portion 96 depending on parts by making thesurface roughness of the flat contact surface 171 vary depending onparts, coating the contact surface with different materials depending onparts, forming the contact surface into a tapered shape such that thedistance from the resistance claw portion 105 varies, and changing thewidth of the surface of the contact surface along the axial directionsuch that the area coming into contact with the resistance claw portion105 varies, for example. The contact surface 171 continuously comes intocontact with the resistance projection portion 96 instead of beingintermittent during the administration. In this manner, the contactsurface 171 (first contact portion) and the resistance claw portion 105(second contact portion) continuously come into contact with each otherwhen the operation unit 20 moves to the structure 40 in the distaldirection. Therefore, it is possible to suspend the administration bystopping the pressing of the operation unit 20 at an arbitrary positionof the operation unit 20 with respect to the structure 40 during theadministration.

In addition, as shown in FIG. 28, the plunger 170 may be formed with aguiding slope 172 for guiding the resistance claw portion 105 to theaccommodation portion 99 on the proximal side of the contact surface 171that comes into contact with the resistance claw portion 105. When themovement amount of the operation unit 20 to the structure 40 in thedistal direction in the second state reaches a predetermined movementamount for the completion of the administration, the guiding slope 172plays a role of coming into contact with the resistance claw portion 105and guiding the resistance claw portion 105 to the accommodation portion99 along the inclination. The state of the device is easily shifted fromthe second state to the third state by forming such a guiding slope 172.Note that the guiding slope 172 may be formed in the plunger 90 shown inFIG. 7.

The biasing force F1 of the first coil spring 12 becomes smaller as theadministration advances and the first coil spring 12 is shrunk.Accordingly, it is easy to establish the above-described expressions (1)to (8) at all times from the start of the administration of a liquid tothe end of the administration of a liquid by setting the contactresistance F3 between the resistance projection portion 96 and thecontact surface 171 to become continuously smaller toward the proximalside of the contact surface. Furthermore, if the difference between thecontact resistance F3 and the biasing force F1 due to the first coilspring 12 is maintained to be constant when the operation unit 20 movesto the structure 40 in the distal direction, it is possible toadminister a liquid at a constant administering rate using constantpressing force. Therefore, it is possible to improve accuracy and safetyof the administration. In addition, the contact resistance F3 may begenerated through contact between the sliding surface 98 and theattachment portion 107.

In addition, the part to which the contact resistance F3 is imparted maynot be between the plunger 90 and the rotary cylinder proximal portion100, and for example, may be between the inner wall surface of thesyringe cylinder 61 and the gasket 21.

In addition, the needle tube 66 communicates with the syringe cylinder61 in advance. However, the needle tube 66 may be a double ended needlethat is provided so as not to communicate with the syringe cylinder andis stuck into the syringe cylinder in use so as to communicatetherewith.

In addition, the structure 40 includes the rotary cylinder proximalportion 100 and the rotary cylinder distal portion 110, but thestructure may be formed of one member. In addition, the structure andthe syringe cylinder may be integrally formed.

In addition, in the first embodiment, the sliding surface 98 is formedin the plunger 90 and the attachment portion 107 coming into contactwith the sliding surface 98 is formed in the rotary cylinder proximalportion 100. The members formed with the sliding surface and theattachment portion are not particularly limited as long as the membersare relatively rotated and move along the axial direction. Accordingly,the sliding surface may be formed in any one of the operation unitcylinder and the structure, and the attachment portion may be formed inthe other one. The sliding surface may be a wall surface of a rib formedto protrude, or a wall surface inside a groove.

What is claimed is:
 1. A liquid administration device for administering a liquid into a living body, comprising: a structure that includes an accommodation body configured to accommodate a liquid therein and a needle configured to communicate with an inside of the accommodation body; an operation unit configured to discharge the liquid inside the accommodation body from the needle by moving toward the structure in a distal direction; a cover member that is movable between a protection position at which the needle is covered and an exposure position at which the needle is exposed; a first biasing member that biases the operation unit toward the structure in the distal direction; and a second biasing member that biases the cover member in the distal direction, wherein the operation unit has a first contact portion and the structure has a second contact portion, the first contact portion and the second contact portion being configured to come into contact with each other when the operation unit moves toward the structure in the distal direction, and wherein the first contact portion and the second contact portion apply a pressing force against each other.
 2. The liquid administration device according to claim 1, wherein the first contact portion and the second contact portion are configured to intermittently come into contact with each other as the operation unit moves toward the structure in the distal direction.
 3. The liquid administration device according to claim 1, wherein the first contact portion and the second contact portion are configured to continuously come into contact with each other as the operation unit moves toward the structure in the distal direction.
 4. The liquid administration device according claim 1, wherein the liquid administration device is configured such that a contact resistance between the first contact portion and the second contact portion changes as the operation unit moves toward the structure in the distal direction.
 5. The liquid administration device according to claim 4, wherein the liquid administration device is configured such that a biasing force due to the first biasing member becomes smaller as the operation unit moves toward the structure in the distal direction, and wherein the liquid administration device is configured such that the contact resistance between the first contact portion and the second contact portion becomes smaller as the operation unit moves toward the structure in the distal direction.
 6. The liquid administration device according to claim 5, wherein the liquid administration device is configured such that a difference between the contact resistance and the biasing force due to the first biasing member is maintained substantially constant as the operation unit moves toward the structure in the distal direction.
 7. The liquid administration device according to claim 6, wherein the liquid administration device comprises at least two first contact portions and at least two second contact portions, and wherein the liquid administration device is configured such that the pressing forces generated by contact between the contact portions are constituted to be substantially canceled by each other in a direction along a plane orthogonal to a movement direction of the operation unit to the structure.
 8. The liquid administration device according to claim 7, wherein the structure is rotatable with respect to the operation unit, and wherein the liquid administration device is configured such that the first contact portion and the second contact portion do not come into contact with each other when the structure rotates with respect to the operation unit.
 9. The liquid administration device according claim 2, wherein the liquid administration device is configured such that a contact resistance between the first contact portion and the second contact portion changes as the operation unit moves toward the structure in the distal direction.
 10. The liquid administration device according to claim 9, wherein the liquid administration device is configured such that a biasing force due to the first biasing member becomes smaller as the operation unit moves toward the structure in the distal direction, and wherein the liquid administration device is configured such that the contact resistance between the first contact portion and the second contact portion becomes smaller as the operation unit moves toward the structure in the distal direction.
 11. The liquid administration device according to claim 10, wherein the liquid administration device is configured such that the difference between the contact resistance and the biasing force due to the first biasing member is maintained substantially constant as the operation unit moves toward the structure in the distal direction.
 12. The liquid administration device according to claim 11, wherein the liquid administration device comprises at least two first contact portions and at least two second contact portions, and wherein the liquid administration device is configured such that the pressing forces generated by contact between the contact portions are constituted to be substantially canceled by each other in a direction along a plane orthogonal to a movement direction of the operation unit to the structure.
 13. The liquid administration device according to claim 12, wherein the structure is rotatable with respect to the operation unit, and wherein the liquid administration device is configured such that the first contact portion and the second contact portion do not come into contact with each other when the structure rotates with respect to the operation unit.
 14. The liquid administration device according claim 3, wherein the liquid administration device is configured such that a contact resistance between the first contact portion and the second contact portion changes as the operation unit moves toward the structure in the distal direction.
 15. The liquid administration device according to claim 14, wherein the liquid administration device is configured such that a biasing force due to the first biasing member becomes smaller as the operation unit moves toward the structure in the distal direction, and wherein the liquid administration device is configured such that the contact resistance between the first contact portion and the second contact portion becomes smaller as the operation unit moves toward the structure in the distal direction.
 16. The liquid administration device according to claim 15, wherein the liquid administration device is configured such that the difference between the contact resistance and the biasing force due to the first biasing member is maintained substantially constant as the operation unit moves toward the structure in the distal direction.
 17. The liquid administration device according to claim 16, wherein the liquid administration device comprises at least two first contact portions and at least two second contact portions, and wherein the liquid administration device is configured such that the pressing forces generated by contact between the contact portions are constituted to be substantially canceled by each other in a direction along a plane orthogonal to a movement direction of the operation unit to the structure.
 18. The liquid administration device according to claim 17, wherein the structure is rotatable with respect to the operation unit, and wherein the liquid administration device is configured such that the first contact portion and the second contact portion do not come into contact with each other when the structure rotates with respect to the operation unit.
 19. The liquid administration device according to claim 1, wherein the liquid administration device comprises at least two first contact portions and at least two second contact portions, and wherein the liquid administration device is configured such that the pressing forces generated by contact between the contact portions are constituted to be substantially canceled by each other in a direction along a plane orthogonal to a movement direction of the operation unit to the structure.
 20. The liquid administration device according to claim 1, wherein the structure is rotatable with respect to the operation unit, and wherein the liquid administration device is configured such that the first contact portion and the second contact portion do not come into contact with each other when the structure rotates with respect to the operation unit. 